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If operation

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Elementwise selecting of one of two inputs given a condition.

BS.Boolean.If (condition, thenValue, elseValue)

Parameters

  • condition: condition according to which element values are selected
  • thenValue: element value selected if condition element is not 0
  • elseValue: element value selected if condition element is 0

Sparse values are currently not supported.

Return Value

A tensor of the dimension of the inputs. If any of the inputs have dimensions of 1, broadcasting is applied; in that case, the output dimension becomes the maximum over the corresponding three arguments' dimensions.

Description

If() selects elements from two inputs based on a condition, in an elementwise fashion. For every input element where condition is non-0, the corresponding element from thenValue is chosen; and where condition is 0, the corresponding elseValue element is chosen.

This function supports broadcasting. For example, it is possible that the condition is a scalar, or one of the inputs is a constant tensor without time dimension.

Example

The elementwise maximum of two inputs can be computed as a combination of Greater() and If():

MyElementwiseMax (a, b) = BS.Boolean.If (Greater (a, b), a, b)

This also works with broadcasting. For example, the linear rectifier can be written with this using a scalar constant as the second input:

MyReLU (x) = MyElementwiseMax (x, Constant(0))